Transverse and/or commutated flux system rotor concepts

ABSTRACT

Disclosed are transverse and/or commutated flux machines and components thereof, and methods of making and using the same. Certain rotors for use in transverse and commutated flux machines may be formed to facilitate a “many to many” flux switch configuration between flux concentrating stator portions having opposite polarities. Other rotors may be formed from a first material, and contain flux switches formed from a second material. Yet other rotors may be machined, pressed, stamped, folded, and/or otherwise mechanically formed. Via use of such rotors, transverse and/or commutated flux machines can achieve improved performance, efficiency, and/or be sized or otherwise configured for various applications.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional of U.S. Provisional No. 61/110,874filed on Nov. 3, 2008 and entitled “ELECTRICAL OUTPUT GENERATING ANDDRIVEN ELECTRICAL DEVICES USING COMMUTATED FLUX AND METHODS OF MAKINGAND USE THEREOF INCLUDING DEVICES WITH TRUNCATED STATOR PORTIONS.”

This application is also a non-provisional of U.S. Provisional No.61/110,879 filed on Nov. 3, 2008 and entitled “ELECTRICAL OUTPUTGENERATING AND DRIVEN ELECTRICAL DEVICES USING COMMUTATED FLUX ANDMETHODS OF MAKING AND USE THEREOF.”

This application is also a non-provisional of U.S. Provisional No.61/110,884 filed on Nov. 3, 2008 and entitled “METHODS OF MACHINING ANDUSING AMORPHOUS METALS OR OTHER MAGNETICALLY CONDUCTIVE MATERIALSINCLUDING TAPE WOUND TORROID MATERIAL FOR VARIOUS ELECTROMAGNETICAPPLICATIONS.”

This application is also a non-provisional of U.S. Provisional No.61/110,889 filed on Nov. 3, 2008 and entitled “MULTI-PHASE ELECTRICALOUTPUT GENERATING AND DRIVEN ELECTRICAL DEVICES WITH TAPE WOUND CORELAMINATE ROTOR OR STATOR ELEMENTS, AND METHODS OF MAKING AND USETHEREOF.”

This application is also a non-provisional of U.S. Provisional No.61/114,881 filed on Nov. 14, 2008 and entitled “ELECTRICAL OUTPUTGENERATING AND DRIVEN ELECTRICAL DEVICES USING COMMUTATED FLUX ANDMETHODS OF MAKING AND USE THEREOF.”

This application is also a non-provisional of U.S. Provisional No.61/168,447 filed on Apr. 10, 2009 and entitled “MULTI-PHASE ELECTRICALOUTPUT GENERATING AND DRIVEN ELECTRICAL DEVICES, AND METHODS OF MAKINGAND USING THE SAME.” The entire contents of all of the foregoingapplications are hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to electrical systems, and in particularto transverse flux machines and commutated flux machines.

BACKGROUND

Motors and alternators are typically designed for high efficiency, highpower density, and low cost. High power density in a motor or alternatormay be achieved by operating at high rotational speed and therefore highelectrical frequency. However, many applications require lowerrotational speeds. A common solution to this is to use a gear reduction.Gear reduction reduces efficiency, adds complexity, adds weight, andadds space requirements. Additionally, gear reduction increases systemcosts and increases mechanical failure rates.

Additionally, if a high rotational speed is not desired, and gearreduction is undesirable, then a motor or alternator typically must havea large number of poles to provide a higher electrical frequency at alower rotational speed. However, there is often a practical limit to thenumber of poles a particular motor or alternator can have, for exampledue to space limitations. Once the practical limit is reached, in orderto achieve a desired power level the motor or alternator must berelatively large, and thus have a corresponding lower power density.

Moreover, existing multipole windings for alternators and electricmotors typically require winding geometry and often complex windingmachines in order to meet size and/or power needs. As the number ofpoles increases, the winding problem is typically made worse.Additionally, as pole count increases, coil losses also increase (forexample, due to resistive effects in the copper wire or other materialcomprising the coil). However, greater numbers of poles have certainadvantages, for example allowing a higher voltage constant per turn,providing higher torque density, and producing voltage at a higherfrequency.

Most commonly, electric motors are of a radial flux type. To a farlesser extent, some electric motors are implemented as transverse fluxmachines and/or commutated flux machines. It is desirable to developimproved electric motor and/or alternator performance and/orconfigurability. In particular, improved transverse flux machines and/orcommutated flux machines are desirable.

SUMMARY

This disclosure relates to transverse and/or commutated flux machines.In an exemplary embodiment, an electrical machine comprises a multipathrotor comprising a first set of elbows on a first side of the rotor anda second set of elbows on a second side of the rotor. The first set ofelbows are positioned on the rotor to align with at least one of a firstset of flux concentrating stator portions having a first polarity. Thesecond set of elbows are positioned on the rotor to align with at leastone of a second set of flux concentrating stator portions having asecond polarity different from the first polarity. The electricalmachine is at least one of a transverse flux machine or a commutatedflux machine.

In another exemplary embodiment, an electrical machine comprises a rotorcomprising a molded rotor frame and a flux switch. The molded rotorframe comprises a first material having a permeability less than 2μ. Theflux switch comprises a second material having a saturation induction inexcess of 1.0 Tesla. The flux switch is coupled to the molded rotorframe. A first surface of the flux switch aligns with a first pole ofthe electrical machine. A second surface of the flux switch aligns witha second pole of the electrical machine in order to conduct magneticflux. The electrical machine is at least one of a transverse fluxmachine or a commutated flux machine.

In yet another exemplary embodiment, a method of forming a rotor for anelectrical machine comprises forming a rotor frame having a plurality oftrenches therein, placing a continuous section of material within atleast two of the plurality of trenches such that the continuous sectionof material has at least one bend, and removing at least a portion ofthe material to form a flux switch. The electrical machine is at leastone of a transverse flux machine or a commutated flux machine.

The contents of this summary section are provided only as a simplifiedintroduction to the disclosure, and are not intended to be used to limitthe scope of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the following description, appended claims, andaccompanying drawings:

FIG. 1A illustrates an exemplary transverse flux machine in accordancewith an exemplary embodiment;

FIG. 1B illustrates an exemplary commutated flux machine in accordancewith an exemplary embodiment;

FIG. 2A illustrates an exemplary axial gap configuration in accordancewith an exemplary embodiment;

FIG. 2B illustrates an exemplary radial gap configuration in accordancewith an exemplary embodiment;

FIG. 3A illustrates an exemplary cavity engaged configuration inaccordance with an exemplary embodiment;

FIG. 3B illustrates an exemplary face engaged configuration inaccordance with an exemplary embodiment;

FIG. 3C illustrates an exemplary face engaged transverse fluxconfiguration in accordance with an exemplary embodiment;

FIG. 4 illustrates electric motor efficiency curves in accordance withan exemplary embodiment;

FIG. 5A illustrates an exemplary tape wound multipath rotor inaccordance with an exemplary embodiment;

FIG. 5B illustrates an exemplary tape wound multipath rotor and anexemplary partial stator in accordance with an exemplary embodiment;

FIG. 5C illustrates an exemplary tape wound multipath rotor and aplurality of exemplary gapped stators in accordance with an exemplaryembodiment;

FIG. 5D illustrates an exemplary multipath rotor providing a “many tomany” flux switch configuration with a plurality of exemplary gappedstators in accordance with an exemplary embodiment;

FIG. 5E illustrates an exemplary multipath rotor providing a “many tomany” flux switch configuration with an exemplary partial stator inaccordance with an exemplary embodiment;

FIG. 6A illustrates an exemplary molded rotor in accordance with anexemplary embodiment;

FIG. 6B illustrates a closer view of an exemplary molded rotorcomprising a rotor frame and a plurality of flux switches in accordancewith an exemplary embodiment;

FIG. 6C illustrates coupling of flux switches within cavities in a rotorframe in accordance with an exemplary embodiment;

FIG. 7A illustrates an exemplary folded rotor in accordance with anexemplary embodiment;

FIG. 7B illustrates an exemplary folded rotor coupled to an exemplarypartial stator in accordance with an exemplary embodiment;

FIG. 7C illustrates exemplary flux switch portions of a folded rotorcoupled to an exemplary partial stator in accordance with an exemplaryembodiment;

FIG. 7D illustrates an exploded view of exemplary flux switch materialand an exemplary folded rotor frame in accordance with an exemplaryembodiment;

FIG. 7E illustrates flux switch material coupled to a folded rotor framein accordance with an exemplary embodiment; and

FIG. 7F illustrates a closer view of flux switch material coupled to afolded rotor frame in accordance with an exemplary embodiment.

DETAILED DESCRIPTION

The following description is of various exemplary embodiments only, andis not intended to limit the scope, applicability or configuration ofthe present disclosure in any way. Rather, the following description isintended to provide a convenient illustration for implementing variousembodiments including the best mode. As will become apparent, variouschanges may be made in the function and arrangement of the elementsdescribed in these embodiments without departing from the scope of theappended claims.

For the sake of brevity, conventional techniques for electrical systemconstruction, management, operation, measurement, optimization, and/orcontrol, as well as conventional techniques for magnetic fluxutilization, concentration, control, and/or management, may not bedescribed in detail herein. Furthermore, the connecting lines shown invarious figures contained herein are intended to represent exemplaryfunctional relationships and/or physical couplings between variouselements. It should be noted that many alternative or additionalfunctional relationships or physical connections may be present in apractical electrical system, for example an AC synchronous electricmotor.

Prior electric motors, for example conventional DC brushless motors,suffer from various deficiencies. For example, many electric motors areinefficient at various rotational speeds and/or loads, for example lowrotational speeds. Thus, the motor is typically operated within a narrowRPM range and/or load range of suitable efficiency. In theseconfigurations, gears or other mechanical approaches may be required inorder to obtain useful work from the motor.

Moreover, many electric motors have a low pole count. Because power is afunction of torque and RPM, such motors must often be operated at a highphysical RPM in order to achieve a desired power density and/orelectrical frequency. Moreover, a higher power density (for example, ahigher kilowatt output per kilogram of active electrical and magneticmotor mass) optionally is achieved by operating the motor at highrotational speed and therefore high electrical frequency. However, highelectrical frequency can result in high core losses and hence lowerefficiency. Moreover, high electrical frequency can result in increasedcost, increased mechanical complexity, and/or decreased reliability.Additionally, high electrical frequency and associated losses createheat that may require active cooling, and can limit the operationalrange of the motor. Heat can also degrade the life and reliability of ahigh frequency machine.

Still other electric motors contain large volumes of copper wire orother coil material. Due to the length of the coil windings, resistiveeffects in the coil lead to coil losses. For example, such lossesconvert a portion of electrical energy into heat, reducing efficiencyand potentially leading to thermal damage to and/or functionaldestruction of the motor.

Moreover, many prior electric motors offered low torque densities. Asused herein, “torque density” refers to Newton-meters produced perkilogram of active electrical and magnetic materials. For example, manyprior electric motors are configured with a torque density from about0.5 Newton-meters per kilogram to about 3 Newton-meters per kilogram.Thus, a certain electric motor with a torque density of 1 Newton-meterper kilogram providing, for example, 10 total Newton-meters of torquemay be quite heavy, for example in excess of 10 kilograms of activeelectrical and magnetic materials. Similarly, another electric motorwith a torque density of 2 Newton-meters per kilogram providing, forexample, 100 total Newton-meters of torque may also be quite heavy, forexample in excess of 50 kilograms of active electrical and magneticmaterials. As can be appreciated, the total weight of these electricmotors, for example including weight of frame components, housings, andthe like, may be significantly higher. Moreover, such prior electricmotors are often quite bulky as a result of the large motor mass. Often,a motor of sufficient torque and/or power for a particular applicationis difficult or even impossible to fit in the available area.

Even prior transverse flux machines have been unable to overcome thesedifficulties. For example, prior transverse flux machines have sufferedfrom significant flux leakage. Still others have offered torquedensities of only a few Newton-meters per kilogram of active electricaland magnetic materials. Moreover, various prior transverse flux machineshave been efficiently operable only within a comparatively narrow RPMand/or load range. Additionally, using prior transverse flux machines togenerate substantial output power often required spinning relativelymassive and complicated components (i.e., those involving permanentmagnets and/or relatively exotic, dense and/or expensive fluxconcentrating or conducting materials) at high rates of speed. Suchhigh-speed operation requires additional expensive and/or complicatedcomponents for support and/or system reliability. Moreover, many priortransverse flux machines are comparatively expensive and/or difficult tomanufacture, limiting their viability.

In contrast, various of these problems can be solved by utilizingtransverse flux machines configured in accordance with principles of thepresent disclosure. As used herein, a “transverse flux machine” and/or“commutated flux machine” may be any electrical machine wherein magneticflux paths have sections where the flux is generally transverse to arotational plane of the machine. In an exemplary embodiment, when amagnet and/or flux concentrating components are on a rotor and/or aremoved as the machine operates, the electrical machine may be a pure“transverse” flux machine. In another exemplary embodiment, when amagnet and/or flux concentrating components are on a stator and/or areheld stationary as the machine operates, the electrical machine may be apure “commutated” flux machine. As is readily apparent, in certainconfigurations a “transverse flux machine” may be considered to be a“commutated flux machine” by fixing the rotor and moving the stator, andvice versa. Moreover, a coil may be fixed to a stator; alternatively, acoil may be fixed to a rotor.

Moreover, there is a spectrum of functionality and device designsbridging the gap between a commutated flux machine and a transverse fluxmachine. Certain designs may rightly fall between these two categories,or be considered to belong to both simultaneously. Therefore, as will beapparent to one skilled in the art, in this disclosure a reference to a“transverse flux machine” may be equally applicable to a “commutatedflux machine” and vice versa.

Moreover, transverse flux machines and/or commutated flux machines maybe configured in multiple ways. For example, with reference to FIG. 2A,a commutated flux machine may be configured with a stator 210 generallyaligned with the rotational plane of a rotor 250. Such a configurationis referred to herein as “axial gap.” In another configuration, withreference to FIG. 2B, a commutated flux machine may be configured withstator 210 rotated about 90 degrees with respect to the rotational planeof rotor 250. Such a configuration is referred to herein as “radialgap.”

With reference now to FIG. 3A, a flux switch 352 in a commutated fluxmachine may engage a stator 310 by extending at least partially into acavity defined by stator 310. Such a configuration is referred to hereinas “cavity engaged.” Turning to FIG. 3B, flux switch 352 in a commutatedflux machine may engage stator 310 by closely approaching two terminalfaces of stator 310. Such a configuration is referred to herein as “faceengaged.” Similar engagement approaches may be followed in transverseflux machines and are referred to in a similar manner.

In general, a transverse flux machine and/or commutated flux machinecomprises a rotor, a stator, and a coil. A flux switch may be located onthe stator or the rotor. As used herein, a “flux switch” may be anycomponent, mechanism, or device configured to open and/or close amagnetic circuit. (i.e., a portion where the permeability issignificantly higher than air). A magnet may be located on the stator orthe rotor. A coil is at least partially enclosed by the stator or therotor. Optionally, flux concentrating portions may be included on thestator and/or the rotor. With momentary reference now to FIG. 1A, anexemplary transverse flux machine 100A may comprise a rotor 150A, astator 110A, and a coil 120A. In this exemplary embodiment, a magnet maybe located on rotor 150A. With momentary reference now to FIG. 1B, anexemplary commutated flux machine 100B may comprise a rotor 150B, astator 110B, and a coil 120B. In this exemplary embodiment, a magnet maybe located on stator 110B.

Moreover, a transverse flux machine and/or commutated flux machine maybe configured with any suitable components, structures, and/or elementsin order to provide desired electrical, magnetic, and/or physicalproperties. For example, a commutated flux machine having a continuous,thermally stable torque density in excess of 50 Newton-meters perkilogram may be achieved by utilizing a polyphase configuration. As usedherein, “continuous, thermally stable torque density” refers to a torquedensity maintainable by a motor, without active cooling, duringcontinuous operation over a period of one hour or more. Moreover, ingeneral, a continuous, thermally stable torque density may be consideredto be a torque density maintainable by a motor for an extended durationof continuous operation, for example one hour or more, without thermalperformance degradation and/or damage.

Moreover, a transverse flux machine and/or commutated flux machine maybe configured to achieve low core losses. By utilizing materials havinghigh magnetic permeability, low coercivity, low hysteresis losses, loweddy current losses, and/or high electrical resistance, core losses maybe reduced. For example, silicon steel, powdered metals, plated powderedmetals, soft magnetic composites, amorphous metals, nanocrystallinecomposites, and/or the like may be utilized in rotors, stators,switches, and/or other flux conducting components of a transverse fluxmachine and/or commutated flux machine. Eddy currents, flux leakage, andother undesirable properties may thus be reduced.

A transverse flux machine and/or commutated flux machine may also beconfigured to achieve low core losses by varying the level of saturationin a flux conductor, such as in an alternating manner. For example, aflux conducting element in a stator may be configured such that a firstportion of the flux conducting element saturates at a first time duringoperation of the stator. Similarly, a second portion of the same fluxconducting element saturates at a second time during operation of thestator. In this manner, portions of the flux conducting element have alevel of magnetic flux density significantly below the saturationinduction from time to time, reducing core loss. For example,significant portions of the flux conducting element may have a level offlux density less than 25% of the saturation induction within the 50% ofthe time of its magnetic cycle. Moreover, any suitable flux densityvariations may be utilized.

Furthermore, a transverse flux machine and/or commutated flux machinemay be configured to achieve low coil losses. For example, in contrastto a conventional electric motor utilizing a mass of copper C in one ormore coils in order to achieve a desired output power P, a particulartransverse flux machine and/or commutated flux machine may utilize onlya small amount of copper C (for example, one-tenth as much copper C)while achieving the same output power P. Additionally, a transverse fluxmachine and/or commutated flux machine may be configured to utilize coilmaterial in an improved manner (for example, by reducing and/oreliminating “end turns” in the coil). In this manner, resistive losses,eddy current losses, thermal losses, and/or other coil losses associatedwith a given coil mass C may be reduced. Moreover, within a transverseflux machine and/or commutated flux machine, a coil may be configured,shaped, oriented, aligned, manufactured, and/or otherwise configured tofurther reduce losses for a given coil mass C.

Additionally, in accordance with principles of the present disclosure, atransverse flux machine and/or commutated flux machine may be configuredto achieve a higher voltage constant. In this manner, the number ofturns in the machine may be reduced, in connection with a higherfrequency. A corresponding reduction in coil mass and/or the number ofturns in the coil may thus be achieved.

Yet further, in accordance with principles of the present disclosure, atransverse flux machine and/or commutated flux machine may be configuredto achieve a high flux switching frequency, for example a flux switchingfrequency in excess of 1000 Hz. Because flux is switched at a highfrequency, torque density may be increased.

With reference now to FIG. 4, a typical conventional electric motorefficiency curve 402 for a particular torque is illustrated. Revolutionsper minute (RPM) is illustrated on the X axis, and motor efficiency isillustrated on the Y axis. As illustrated, a conventional electric motortypically operates at a comparatively low efficiency at low RPM. Forthis conventional motor, efficiency increases and then peaks at aparticular RPM, and eventually falls off as RPM increases further. As aresult, many conventional electric motors are often desirably operatedwithin an RPM range near peak efficiency. For example, one particularprior art electric motor may have a maximum efficiency of about 90% atabout 3000 RPM, but the efficiency falls off dramatically at RPMs thatare not much higher or lower.

Gearboxes, transmissions, and other mechanical mechanisms are oftencoupled to an electric motor to achieve a desired output RPM or otheroutput condition. However, such mechanical components are often costly,bulky, heavy, and/or impose additional energy losses, for examplefrictional losses. Such mechanical components can reduce the overallefficiency of the motor/transmission system. For example, an electricmotor operating at about 90% efficiency coupled to a gearbox operatingat about 70% efficiency results in a motor/gearbox system having anoverall efficiency of about 63%. Moreover, a gearbox may be largerand/or weigh more or cost more than the conventional electric motoritself. Gearboxes also reduce the overall reliability of the system.

In contrast, with continuing reference to FIG. 4 and in accordance withprinciples of the present disclosure, a transverse and/or commutatedflux machine efficiency curve 404 for a particular torque isillustrated. In accordance with principles of the present disclosure, atransverse and/or commutated flux machine may rapidly reach a desirableefficiency level (for example, 80% efficiency or higher) at an RPM lowerthan that of a conventional electric motor. Moreover, the transverseand/or commutated flux machine may maintain a desirable efficiency levelacross a larger RPM range than that of a conventional electric motor.Additionally, the efficiency of the transverse and/or commutated fluxmachine may fall off more slowly past peak efficiency RPM as compared toa conventional electric motor.

Furthermore, in accordance with principles of the present disclosure, atransverse and/or commutated flux machine may achieve a torque densityhigher than that of a conventional electric motor. For example, in anexemplary embodiment a transverse and/or commutated flux machine mayachieve a continuous, thermally stable torque density in excess of 100Newton-meters per kilogram.

Thus, in accordance with principles of the present disclosure, atransverse and/or commutated flux machine may desirably be employed invarious applications. For example, in an automotive application, atransverse and/or commutated flux machine may be utilized as a wheel hubmotor, as a direct driveline motor, and/or the like. Moreover, in anexemplary embodiment having a sufficiently wide operational RPM range,particularly at lower RPMs, a transverse and/or commutated flux machinemay be utilized in an automotive application without need for atransmission, gearbox, and/or similar mechanical components.

An exemplary electric or hybrid vehicle embodiment comprises atransverse flux motor for driving a wheel of the vehicle, wherein thevehicle does not comprise a transmission, gearbox, and/or similarmechanical component(s). In this exemplary embodiment, the electric orhybrid vehicle is significantly lighter than a similar vehicle thatcomprises a transmission-like mechanical component. The reduced weightmay facilitate an extended driving range as compared to a similarvehicle with a transmission like mechanical component. Alternatively,weight saved by elimination of the gearbox allows for utilization ofadditional batteries for extended range. Moreover, weight saved byelimination of the gearbox allows for additional structural material forimproved occupant safety. In general, a commutated flux machine having abroad RPM range of suitable efficiency may desirably be utilized in avariety of applications where a direct-drive configuration isadvantageous. For example, a commutated flux machine having anefficiency greater than 80% over an RPM range from only a few RPMs toabout 2000 RPMs may be desirably employed in an automobile.

Moreover, the exemplary transmissionless electric or hybrid vehicle mayhave a higher overall efficiency. Stated otherwise, the exemplaryvehicle may more efficiently utilize the power available in thebatteries due to the improved efficiency resulting from the absence of atransmission-like component between the motor and the wheel of thevehicle. This, too, is configured to extend driving range and/or reducethe need for batteries.

Additionally, the commutated flux machine is configured to have a hightorque density. In accordance with principles of the present disclosure,the high torque density commutated flux machine is also well suited foruse in various applications, for example automotive applications. Forexample, a conventional electric motor may have a torque density ofbetween about 0.5 to about 3 Newton-meters per kilogram. Additionaltechniques, for example active cooling, can enable a conventionalelectric motor to achieve a torque density of up to about 50Newton-meters per kilogram. However, such techniques typically addsignificant additional system mass, complexity, bulk, and/or cost.Additionally, such conventional electric motors configured to producecomparatively high amounts of torque, for example the Siemens 1FW6motor, are limited to comparatively low RPM operation, for exampleoperation below 250 RPMs.

In contrast, in accordance with principles of the present disclosure, anexemplary passively cooled transverse flux machine and/or commutatedflux machine may be configured with a continuous, thermally stabletorque density in excess of 50 Newton-meters per kilogram. As usedherein, “passively cooled” is generally understood to refer to systemswithout cooling components requiring power for operation, for examplewater pumps, oil pumps, cooling fans, and/or the like. Moreover, thisexemplary transverse flux machine and/or commutated flux machine may beconfigured with a compact diameter, for example a diameter less than 14inches. Another exemplary transverse flux machine and/or commutated fluxmachine may be configured with a continuous, thermally stable torquedensity in excess of 100 Newton-meters per kilogram and a diameter lessthan 20 inches. Accordingly, by utilizing various principles of thepresent disclosure, exemplary transverse flux machines and/or commutatedflux machines may be sized and/or otherwise configured and/or shaped ina manner suitable for mounting as a wheel hub motor in an electricvehicle, because the transverse flux machine and/or commutated fluxmachine is significantly lighter and/or more compact than a conventionalelectric motor. In this manner, the unsprung weight of the resultingwheel/motor assembly can be reduced. This can improve vehicle handlingand reduce the complexity and/or size of suspension components.

Further, in accordance with principles of the present disclosure, atransverse flux machine and/or commutated flux machine may desirably beutilized in an electromechanical system having a rotating portion, forexample a washing machine or other appliance. In one example, aconventional washing machine typically utilizes an electric motorcoupled to a belt drive to spin the washer drum. In contrast, atransverse flux machine and/or commutated flux machine may be axiallycoupled to the washer drum, providing a direct drive configuration andeliminating the belt drive element. Alternatively, a transverse fluxmachine and/or commutated flux machine, for example one comprising apartial stator, may be coupled to a rotor. The rotor may have a commonaxis as the washer drum. The rotor may also be coupled directly to thewasher drum and/or integrally formed therefrom. In this manner, atransverse flux machine and/or commutated flux machine may providerotational force for a washing machine or other similarelectromechanical structures and/or systems.

Moreover, in accordance with principles of the present disclosure, atransverse flux machine and/or commutated flux machine may desirably beutilized to provide mechanical output to relatively lightweight vehiclessuch as bicycles, scooters, motorcycles, quads, golf carts, or othervehicles. Additionally, a transverse flux machine and/or commutated fluxmachine may desirably be utilized in small engine applications, forexample portable generators, power tools, and other electricalequipment. A transverse flux machine and/or commutated flux machine maydesirably be utilized to provide mechanical output to propeller-drivendevices, for example boats, airplanes, and/or the like. A transverseflux machine and/or commutated flux machine may also desirably beutilized in various machine tools, for example rotating spindles, tablesconfigured to move large masses, and/or the like. In general, transverseflux machines and/or commutated flux machines may be utilized to provideelectrical and/or mechanical input and/or output to and/or from anysuitable devices.

In various exemplary embodiments, a commutated flux machine may comprisea rotor having a multipath configuration. In general, a multipath rotorfor a commutated flux machine comprises any structure, assembly, and/ormechanism or device configured to provide a plurality of flux pathsbetween a plurality of first flux concentrating stator portions and aplurality of second flux concentrating stator portions. Stated anotherway, a multipath rotor can provide a “many to many” flux switchconfiguration for a commutated flux machine.

In an exemplary embodiment, and with reference now to FIG. 5A, amultipath rotor 550 comprises a generally ring-shaped structure having afirst set of “elbows” 552 on a first side of multipath rotor 550.Multipath rotor 550 further comprises a second set of elbows 554 on asecond side of multipath rotor 550. In a commutated flux machine, atleast a portion of multipath rotor 550 is configured to act as a fluxswitch for a stator. For example, one or more elbows of the first set ofelbows 552, or portions thereof, may each act as a flux switch.Similarly, one or more elbows of the second set of elbows 554, orportions thereof, may each act as a flux switch. Flux may thus beconducted across an air gap in a stator between one or more of the firstset of elbows 552 and one or more of the second set of elbows 554.

In another exemplary embodiment, multipath rotor 550 comprises agenerally ring-shaped structure having a first set of trenches 562,inscribed on a first side of the ring. Portions of the ring remainingbetween the first set of trenches comprise a first set of flux switches.Multipath rotor 550 further comprises a second set of trenches 564inscribed on a second side of the ring. Portions of the ring remainingbetween the second set of trenches comprise a second set of fluxswitches. In accordance with one exemplary embodiment, for a multipathrotor 550 having a radial gap configuration, the first side may also beconsidered to be the outside of the ring, and the second side may alsobe considered to be the inside of the ring.

In accordance with various exemplary embodiments, trenches 562 and/or564 may comprise various shapes. For example, a trench may comprise acylindrical shape, elliptical shape, a triangular shape, a rectangularshape, a trapezoidal shape, and/or any suitable shape(s).

In accordance with various exemplary embodiments, an elbow may be formedby repeatedly removing partially cylindrical portions from a generallyring-shaped block of material. In this manner, an elbow may be formedsuch that the elbow comprises two arcuate sides, and the elbow may taperoutwardly.

In another example, an elbow may be formed by repeatedly removinggenerally V-shaped portions from a generally ring-shaped block ofmaterial. In this manner, an elbow may be formed such that the elbowcomprises two generally planar sides. Moreover, the depth, angle, and/orother parameters of the generally V-shaped cut may be varied. In thismanner, the thickness of the elbows may be varied.

In yet another example, multipath rotor 550 may be formed by molding adesired shape from powdered metal or other suitable material. Multipathrotor 550 may also be formed by cutting layers of a planar material, forexample tape-like steel, into a configuration having various elbowand/or trench shapes. The tape-like material may then be wound about amandrel, for example a mandrel configured with guidance features forcontrolling alignment of the tape-like material. In this manner,position, size, and/or other tolerances may be controlled duringcreation of multipath rotor 550.

Furthermore, in between each trench and/or v-shaped removed portion, aportion of multipath rotor 550 may remain at its original shape. Thus,in various exemplary embodiments, elbows 552 and/or 554 may representun-cutaway portions. The center to center distance between adjacentelbows may be any suitable distance. In various exemplary embodiments,the center to center distance may be a function of a pole pitch in acommutated flux machine. The on-center spacing between the elbows maysimilarly be varied, for example in order to cause an on-center spacingbetween certain elbows to align with an on-center spacing between fluxconcentrating stator portions in a particular stator.

In addition, the edge to edge distance for any one elbow may be anysuitable distance. In certain exemplary embodiments, the edge to edgedistance for any one elbow may be considered to be a switch thickness.

The switch area of multipath rotor 550 may be selected to facilitate useof multipath rotor 550 with a particular stator. With momentaryreference to FIG. 1B, in a cavity engaged configuration, “switch area”refers to the product of a switch thickness (for example, S_(T)) and anengagement depth (for example, E_(D)). In a cavity engagedconfiguration, engagement depth E_(D) may be considered to be a lengthalong a switch (for example, a length along a portion of rotor 150B)where it extends into a cavity (for example, the cavity at leastpartially defined by stator 110B).

With momentary reference to FIG. 3C, in a face engaged configuration,“switch area” refers to the product of a switch thickness (for example,S_(T)) and an engagement depth (for example, E_(D)). In a face engagedconfiguration, engagement depth E_(D) may be considered to be a lengthalong a switch (for example, a length along a portion of stator 310)where it closely approaches a corresponding portion of a rotor and/orstator (for example, rotor 350).

In an exemplary embodiment, one or more elbows may be formed onmultipath rotor 550 in order to create a desired switch area on asurface of each elbow, for example at the end of each elbow.

In general, one or more elbows and/or other portions of multipath rotor550 may be formed via any suitable process, technique, or methodology,as desired, in order to create a flux switch having a desired switcharea at a surface of an elbow. Additionally, as will be appreciated byone skilled in the art, similar processes, techniques, and/ormethodologies may be applied to form other electrical components, forexample single-path rotors, stators, flux switches, and/or other fluxconducting portions of a commutated flux machine.

Moreover, multipath rotor 550 may comprise any suitable elbows,extensions, extrusions, protrusions, trenches, gaps, flanges,geometries, and/or structures configured to provide a plurality of fluxpaths between a plurality of first flux concentrating stator portionsand a plurality of second flux concentrating stator portions. Forexample, multipath rotor 550 may be configured with a sawtooth pattern,a zig-zag pattern, an interlocking diamond pattern, a square wavepattern, and/or the like, or combinations of the same.

In various exemplary embodiments, at least a portion of multipath rotor550 may be configured with a varied on-center distance between elbows.For example, a first portion of multipath rotor 550 may be configuredwith a first on-center distance D1 between adjacent elbows.Additionally, a second portion of multipath rotor 550 may be configuredwith a second on-center distance D2 between adjacent elbows. D1 and D2may be the same, or they may be different. For example, D2 may be twicethe distance D1. D2 may also be three times the distance D1. Moreover,D1 and D2 may be any suitable distances and may have any suitablerelationship.

Varied on-center distances may be advantageous. For example, in anexemplary embodiment, when multipath rotor 550 is coupled to a partialstator and/or a gapped stator in a commutated flux machine, multipathrotor 550 may be configured to cause the commutated flux machine toproduce a first torque when the first portion of multipath rotor 550engages a stator. Similarly, multipath rotor 550 may be configured tocause the commutated flux machine to produce a second torque when thesecond portion of multipath rotor 550 engages a stator. The secondtorque may be different from the first torque, for example due to thefact that as the distance between elbows on multipath rotor 550increases, the number of flux concentrating stator portions engaged bymultipath rotor 550 decreases.

In various exemplary embodiments, when a commutated flux machine isoperated as a generator, multipath rotor 550 may be configured to aligna “higher torque” portion of multipath rotor 550 (i.e., a portion ofmultipath rotor 550 having a smaller on-center distance between adjacentelbows) with a stator at a time when mechanical input is comparativelystrong (for example, during the power stroke of a 4-stroke engine).Similarly, multipath rotor 550 may be configured to align a “lowertorque” portion of multipath rotor 550 (i.e., a portion of multipathrotor 550 having a larger on-center distance between adjacent elbows)with a stator at a time when mechanical input is less strong (forexample, during the exhaust, intake, and/or compression strokes of a4-stroke engine). In this manner, a commutated flux machine may beconfigured to more efficiently convert a varying mechanical input, forexample mechanical output generated by a 4-stroke piston engine, intoelectrical energy.

In accordance with various exemplary embodiments, multipath rotor 550may be formed in any suitable manner to provide a plurality of fluxpaths between a plurality of first flux concentrating stator portionsand a plurality of second flux concentrating stator portions. Forexample, multipath rotor 550 may be formed by removing material from aring-shaped piece of monolithic material (e.g., silicon steel) aspreviously discussed. Moreover, multipath rotor 550 may be cast,pressed, sintered, die-cut, machined, stamped, bonded, laminated,polished, smoothed, bent, molded, plated, coated, and/or otherwiseshaped and/or formed via any suitable method. For example, multipathrotor 550 may be created via a method configured to create a first setof elbows and a second set of elbows along opposing sides of a generallyring-like structure.

In one exemplary embodiment, and with reference now to FIG. 5C,multipath rotor 550 is formed by laminating and/or otherwise bondingmultiple layers of material. For example, a particular multipath rotor550 intended for use in a radial gap commutated flux machine may beformed from multiple layers of laminated planar material. Multipathrotor 550 may then be cut or otherwise formed from the multiple-layermaterial, for example via water jet cutting, laser cutting, and/or anyother suitable technique or process. Alternatively, individual layers ofplanar material may first be cut, and then stacked, laminated, pressed,and/or otherwise bonded or aligned in order to form multipath rotor 550.The resulting multipath rotor 550 may be considered to be comprised of a“stack” of similar multipath rotors 550, each stacked multipath rotor550 being of comparatively thin planar material.

When intended for use in a radial gap commutated flux machine, the planeof each layer of the rotor stack is substantially parallel to the planeof rotation of the rotor. Thus, when cavity engaged with a radial gapstator, for example stator 510 at least partially enclosing coil 520,the plane of each layer of the rotor stack traverses the resulting airgap. Stated another way, flux within multipath rotor 550 may remainsubstantially within a layer of the rotor stack, rather than acrosslayers within the rotor stack. Because the layers of planar material inthe rotor stack tend to conduct magnetic flux substantially within thelayer, magnetic flux is conducted more efficiently. Because electricalresistance is higher across the layers, flux leakage, eddy currents, andother undesirable effects are thus reduced.

In accordance with another exemplary embodiment, and with referenceagain to FIG. 5A, a particular multipath rotor 550 intended for use inan axial gap commutated flux machine may be formed from a wound planarmaterial. For example, a planar material may be wound about a mandrel.Multipath rotor 550 may then be cut or otherwise formed from the woundplanar material, for example via water jet cutting, laser cutting,and/or any other suitable technique or process. When multipath rotor 550so formed is cavity engaged with an axial gap stator, the plane of eachwound layer of the rotor traverses the resulting air gap. As before,because the layers of wound planar material tend to conduct magneticflux substantially within the layer, and because electrical resistanceis higher across the layers, flux leakage, eddy currents, and otherundesirable effects are reduced.

In various exemplary embodiments, multipath rotor 550 is formed frommultiple types of stacked, wound, or otherwise joined material. Forexample, a particular multipath rotor 550 may be formed from alternatinglayers of planar material. The layers may have different properties. Inan exemplary embodiment, multipath rotor 550 is formed from alternatinglayers of amorphous metal (e.g., Metglas® 2605SA1) and nanocrystallinecomposite. In another exemplary embodiment, multipath rotor 550 isformed from alternating layers of silicon steel and nanocrystallinecomposite. In various other exemplary embodiments, multipath rotor 550is formed from a layer of amorphous metal and a layer of nanocrystallinecomposite wound together about a mandrel. In yet other exemplaryembodiments, multipath rotor 550 is formed from alternating layers ofthree or more materials. Moreover, multipath rotor 550 may be formedfrom any suitable combination of layers and/or materials joined by anysuitable process, for example two layers of a first material, then onelayer of a second material, then again two layers of the first material,then one layer of the second material, and so on.

By utilizing layers of multiple materials in this manner, multipathrotor 550 can have improved mechanical, magnetic, and/or otherproperties. For example, multipath rotor 550 may have improvedmachineability while retaining desirable magnetic, thermal, electrical,or other properties. In an exemplary embodiment, multipath rotor 550formed from multiple layered materials is configured with a bulksaturation induction in excess of 1.0 Tesla. In another exemplaryembodiment, multipath rotor 550 formed from multiple layered materialsis configured with a bulk permeability in excess of 1,000μ.

Moreover, in addition to multipath rotor 550, other electricalcomponents, including stators, flux switches, coils, flux concentrators,molded rotors, and/or the like, may be at least partially formed from,contain, and/or comprise layers of material, molded materials, and/ormultiple materials as discussed hereinabove. All such components andmethodologies are considered to be within the scope of the presentdisclosure.

In various exemplary embodiments, multipath rotor 550 may be utilized inconnection with a radial gap commutated flux machine. Moreover, invarious other exemplary embodiments, multipath rotor 550 may be utilizedin connection with an axial gap commutated flux machine, for example acommutated flux machine configured with a partial stator (see, forexample, FIG. 5B). In general, multipath rotor 550 may be used in anysuitable commutated flux machine and/or transverse flux machine, asdesired.

Moreover, in various exemplary embodiments, the engagement depth ofmultipath rotor 550 into a stator may be varied. The air gap betweenmultipath rotor 550 and the stator may also be controlled and/oradjusted, for example by coupling multipath rotor 550 to a stator viaguide wheels, bumpers, and/or the like. By varying the engagement depthof multipath rotor 550 into a cavity at least partially defined by astator, various properties of a commutated flux machine may desirably becontrolled, varied, and/or otherwise modified.

For example, reducing the engagement depth may result in a reducedvoltage constant. Similarly, reducing the engagement depth may result ina reduced torque constant. Moreover, reducing the engagement depth mayincrease the efficiency of a commutated flux machine. Reduced engagementdepth may also permit higher RPM operation with the same driveelectronics. A desired performance characteristic, for example operationat a particular efficiency level, may thus be obtained by varying theengagement depth in a suitable manner.

Additionally, when a commutated flux machine is operated as a generator,varying the engagement depth can provide a suitable response to avarying load. For example, at a particular load, a first engagementdepth may be sufficient to produce a desired output. At a larger load, asecond engagement depth may be sufficient to produce a desired output.The engagement depth may thus be varied responsive to changing loadconditions on the generator.

With reference now to FIG. 5B, in various exemplary embodimentsmultipath rotor 550 may be operatively coupled to a partial stator. Withfurther reference to FIG. 5D, multipath rotor 550 may be constructedsuch that a particular elbow A1 of a first set of elbows 552 aligns witha first flux concentrating stator portion having a first polarity. Anadjacent elbow A2 of the first set of elbows 552 aligns with a secondflux concentrating stator portion having a same polarity as the firstpolarity. Simultaneously, a particular elbow B1 of a second set ofelbows 554 aligns with a third flux concentrating stator portion havingan opposite polarity as the first polarity. Similarly, an adjacent elbowB2 of the second set of elbows 554 aligns with a fourth fluxconcentrating stator portion also having an opposite polarity as thefirst polarity, and so on.

In this manner, magnetic flux may be conducted through multipath rotor550 from either of A1 or A2 to either of B1 or B2 (or vice versa), asshown by the illustrated arrows. Moreover, because each of the fluxswitches associated with the first set of elbows 552 is magneticallycoupled to every other flux switch of the first set of elbows 552, andto every flux switch associated with the second set of elbows 554,magnetic flux may be conducted through multipath rotor 550 from any fluxswitch engaging a flux concentrating stator portion of a first polarityto any flux switch engaging a flux concentrating stator portion having apolarity opposite the first polarity. Additionally, with momentaryreference to FIG. 5E, flux from any particular flux switch (for example,switch B1) may be conducted to multiple other flux switches (forexample, switches A1, A2, and A3).

Thus, in general, in an exemplary embodiment, multipath rotor 550 isconfigured such that magnetic flux may be conducted within a commutatedflux machine in a “many to many” arrangement. Stated another way,magnetic flux may flow from any of a plurality of magnetic flux“sources” (i.e., flux concentrating stator portions having a firstpolarity) into any of a plurality of magnetic flux “sinks” (i.e., fluxconcentrating stator portions having a polarity opposite the firstpolarity). In other words, magnetic flux may enter multipath rotor 550at any of the first set of elbows 552, and depart the rotor at any ofthe second set of elbows 554, or vice versa.

Additionally, in a “one to one” flux switching configuration, a fluxconcentrating stator portion located at or near the edge of a partialstator may at times be unutilized. This is because a flux switchassociated with that flux concentrating stator portion extends out pastthe end of the partial stator, and thus from time to time does notengage with a corresponding flux concentrating stator portion having anopposite polarity. Via use of multipath rotor 550 providing a “many tomany” flux switching configuration, a flux concentrating stator portionlocated at or near the edge of a partial stator is provided with a fluxpath to a flux concentrating stator portion of opposite polarity whenflux switches on multipath rotor 550 are spaced and/or otherwise alignedin a suitable manner. Thus, flux available in each flux concentratingstator portion in the partial stator may be more fully utilized and/ormore effectively switched, leading to improved torque density, improvedoutput power, and so forth.

Moreover, in addition to being suitable for use with a partial stator,in various exemplary embodiments multipath rotor 550 may desirably beutilized in connection with a gapped stator, a fully circular stator,and/or any other stator for a commutated flux machine and/orcombinations of the same.

In general, multipath rotor 550 may be designed, shaped, and/orotherwise configured, as desired, for use in an electrical machine, forexample a commutated flux machine and/or transverse flux machine. Invarious exemplary embodiments, with momentary reference to FIG. 5A,multipath rotor 550 may be configured with a switch area S_(A), whereS_(A) is the product of a switch thickness and an engagement depth.Similarly, a corresponding stator may be configured with a fluxconcentrator area C_(A), where C_(A) is the product of a fluxconcentrator thickness and an engagement depth.

In various exemplary embodiments, and with reference to FIG. 5E,multipath rotor 550 is configured for use in a cavity engaged commutatedflux machine. In these embodiments, multipath rotor 550 is configured toat least partially engage within a cavity defined by a stator in orderto conduct magnetic flux, as illustrated by FIG. 5E. In other exemplaryembodiments, multipath rotor 550 is configured for use in a face engagedcommutated flux machine. In these embodiments, multipath rotor 550 isconfigured to closely approach a stator in order to conduct magneticflux. Additionally, a molded rotor body may have flux switchesconfigured in a multipath pattern mounted on a face of the molded rotorbody.

Moreover, a suitable rotor providing a “many to many” flux switchconfiguration, for example multipath rotor 550, may be utilized invarious transverse and/or commutated flux machines, as desired.

It will be readily appreciated by one skilled in the art that variousprinciples of the present disclosure illustrated hereinabove withrespect to multipath rotors, for example principles of construction anduse, are equally suitable for utilization in connection with single pathrotors, flux switches, flux concentrators, stators, and/or other fluxconducting components of various transverse and/or commutated fluxmachines.

In addition to multipath type rotors and tape wound rotors disclosedhereinabove, principles of the present disclosure contemplate “molded”rotors for transverse and/or commutated flux machines. In accordancewith various exemplary embodiments, a molded rotor for a commutated fluxmachine may comprise any structure, assembly, and/or mechanism or deviceconfigured to provide a flux path between a first flux concentratingstator portion and a second flux concentrating stator portion. Moreover,in certain exemplary embodiments a molded rotor may function as amultipath rotor.

In an exemplary embodiment, with reference now to FIGS. 6A to 6C, amolded rotor 650 comprises a rotor body 656 and a plurality of fluxswitches 658. Flux switches 658 are coupled to rotor body 656. Moldedrotor 650 is configured to interface with a stator having one or moreflux concentrating stator portions.

Molded rotor body 656 may comprise any material or combinations ofmaterials configured to support, guide, align, and/or otherwiseinterface with flux switches 658. In various exemplary embodiments,molded rotor body 656 comprises a material having a desirable lowpermeability, for example a permeability only slightly larger than airor less than that of air (i.e., less than about 2μ). Molded rotor body656 may also comprise a non-ferrous material. Molded rotor body 656 mayalso comprise a material having a high thermal conductivity. Moldedrotor body 656 may also comprise a material having a high bulkelectrical resistivity. In various exemplary embodiments, molded rotorbody 656 comprises one or more of ceramics, plastics, ceramic-filledplastics, glass-filled plastics, liquid crystal polymers, and/orcombinations of the same.

Molded rotor body 656 may be formed via any suitable method and/orprocess. For example, in various exemplary embodiments molded rotor body656 may be formed via one or more of injection molding, compressionmolding, pressing, sintering, cutting, grinding, abrading, polishing,and/or the like.

In an exemplary embodiment, molded rotor body 656 is monolithic. Invarious exemplary embodiments, molded rotor body 656 comprises multiplecomponents joined, fastened, welded, and/or otherwise engaged in orderto form molded rotor body 656. In other exemplary embodiments, moldedrotor body 656 comprises multiple materials. Moreover, molded rotor body656 may comprise various non-ferrous metals, for example aluminum, asdesired. Molded rotor body 656 may also comprise various cavities,trenches, extrusions, bosses, slots, and/or the like, configured to atleast partially accept, bond with, contain, and/or couple to fluxswitches 658.

Flux switches 658 may comprise any materials, shapes, and/or structuresconfigured to conduct magnetic flux, for example between fluxconcentrating stator portions. In various exemplary embodiments, fluxswitches 658 comprise one or more of powdered metals, silicon steel,cobalt steel, nickel steel, amorphous metals (e.g., Metglas® 2605SA1),or nanocrystalline composites. Moreover, flux switches 658 may comprisemonolithic material. Flux switches 658 may also comprise layeredmaterial. Further, flux switches 658 may comprise any suitable materialor materials usable to conduct magnetic flux. For example, flux switches658 may be configured with a suitable bulk saturation induction, forexample a bulk saturation induction in excess of 1.0 Tesla. Fluxswitches 658 may also be configured with a suitable bulk permeability,for example a permeability in excess of 1,000μ. Moreover, flux switches658 may also comprise materials having a high electrical resistivity.

In certain exemplary embodiments, with reference to FIG. 6B, fluxswitches 658 may be configured to be fully contained within molded rotorbody 656 when coupled to molded rotor body 656. In these configurations,molded rotors 650 are well suited for use with commutated flux machineshaving a face engaged stator configuration. In other exemplaryembodiments, flux switches 658 are configured to extend at leastpartially beyond molded rotor body 656 when coupled to molded rotor body656. In these configurations, molded rotors 650 are well suited for usewith commutated flux machines having a cavity engaged statorconfiguration. However, as will be readily appreciated by one skilled inthe art, partially extended flux switches 658 may also be suited for usein a face engaged configuration, and fully contained flux switches 658may also be suited for use in a cavity engaged stator configuration.

In various exemplary embodiments, flux switches 658 may be sized,aligned, angled, spaced, placed, and/or otherwise configured to providea “one to one” connection between flux concentrating stator portions.Stated another way, a particular flux switch 658 may be configured tosimultaneously engage a first flux concentrating stator portion having afirst polarity and a second flux concentrating stator portion having anopposite polarity. In this manner, via a particular flux switch 658, aflux path is provided across an air gap in a stator between one magneticflux “source” and one magnetic flux “sink.”

In other exemplary embodiments, one or more flux switches 658 may belinked, joined, connected, aligned, placed, and/or otherwise configuredwithin molded rotor 650 to provide a “many to many” connection betweenflux concentrating stator portions. Stated another way, in theseembodiments magnetic flux may flow through molded rotor 650 from any oneof a plurality of magnetic flux “sources” (i.e., flux concentratingstator portions having a first polarity) across an air gap in a statorinto any of a plurality of magnetic flux “sinks” (i.e., fluxconcentrating stator portions having an opposite polarity as the firstpolarity).

By providing a “many to many” flux switch arrangement, molded rotor 650may improve performance of various electrical machines, includingcommutated flux machines utilizing partial and/or gapped stators. Forexample, in a “one to one” flux switching configuration, a fluxconcentrating stator portion located at or near the edge of a partialstator may at times be unutilized. This is because a flux switchassociated with that flux concentrating stator portion extends out pastthe end of the partial stator, and thus from time to time does notengage with a corresponding flux concentrating stator portion having anopposite polarity. Via use of molded rotor 650 providing a “many tomany” flux switching configuration, a flux concentrating stator portionlocated at or near the edge of a partial stator is provided with a fluxpath to a flux concentrating stator portion of opposite polarity whenflux switches 658 on molded rotor 650 are spaced and/or otherwisealigned in a suitable manner. Thus, each flux concentrating statorportion in the partial stator may be more fully utilized, leading toimproved torque density, improved output power, and so forth.

By coupling a molded rotor body 656 to one or more flux switches 658,the resulting molded rotor 650 may have desirable mechanical, thermal,magnetic, and/or other properties. For example, molded rotor body 656may comprise a material significantly less dense than material withinflux switches 658. The mass of molded rotor 650 may thus be reduced,which can be desirable in order to reduce total rotating mass in amotor. Further, molded rotor body 656 may comprise a material having alow permeability compared to material within flux switches 658. Fluxleakage within molded rotor 650 may thus be desirably reduced.

Moreover, molded rotor body 656 may comprise a less expensive materialthan material within flux switches 658. Molded rotor 650 may thus beproduced in a more cost-effective manner. Molded rotor body 656 may alsocomprise a material more easily machined than material within fluxswitches 658. Higher dimensional accuracy of, improved strength of,and/or reduced difficulty of production of molded rotor 650 may thus beachieved. Molded rotor body 656 may also comprise fan-like portions orother components configured to deflect air, for example in order todirect airflow across a stator portion responsive to rotation of moldedrotor body 656. In this manner, improved cooling for a commutated fluxmachine may be achieved.

Moreover, in various exemplary embodiments, a particular molded rotorbody 656 may also be configured to accept, contain, and/or otherwisecouple with a particular multipath rotor 550, as desired. In thismanner, molded rotor body 656 may provide structural support tomultipath rotor 550, allowing components of multipath rotor 550 to bemodified, for example to make components of multipath rotor thinnerand/or smaller. In this manner, components of multipath rotor 550 mayalso be selected based primarily on magnetic considerations, as moldedrotor body 656 may provide mechanical, thermal, and/or structuralsupport to multipath rotor 550.

In addition to the rotors discussed hereinabove, principles of thepresent disclosure contemplate “folded” rotors. As used herein, a“folded” rotor is a rotor comprising a material at least partiallyfolded, bent, and/or otherwise shaped to form a flux switch. Inaccordance with various exemplary embodiments, a folded rotor for atransverse flux machine and/or commutated flux machine may comprise anystructure, assembly, materials, and/or mechanism or device configured toprovide a flux path between a first flux concentrating stator portionand a second flux concentrating stator portion. Moreover, in certainexemplary embodiments a folded rotor may function as a multipath rotor.

In an exemplary embodiment, with reference now to FIGS. 7A-7F, a foldedrotor 750 comprises a rotor body 756 and flux conducting material 758.Flux conducting material 758 is coupled to rotor body 756. Folded rotor750 is configured to interface with a stator having one or more fluxconcentrating stator portions. In various exemplary embodiments, fluxconducting material 758 comprises a layered material, for example layersof amorphous metal.

In various exemplary embodiments, portions of flux conducting material758 may be formed to function as flux switches. For example, acontinuous portion of flux conducting material 758 may be placed atleast partially within one or more trenches, grooves, and/or otherpathways and/or features on rotor body 756. For example, with momentaryreference to FIG. 7F, flux conducting material 758 may be “threaded”and/or otherwise interleaved and/or passed through alternating trenches,for example in a serpentine manner, a back-and-forth manner, and/or thelike.

In various exemplary embodiments, multiple segments of flux conductingmaterial 758 may be utilized. For example, a first segment of fluxconducting material 758A may be threaded through a first portion ofrotor body 756. A second segment of flux conducting material 758B may bethreaded through a second portion of rotor body 756. With referenceagain to FIG. 7F, the ends of segments 758A and 758B may be adjacent,abutting, and/or otherwise closely aligned, for example at junction J1.Additional flux conducting segments, for example segment 758C, may beconfigured in a similar manner, and may connect with and/or otherwise beadjacent to and/or abut other portions of flux conducting material 758,for example at junction J2. In this manner, flux conducting material758, for example flux conducting material 758 available in a limitedlength, may be fully threaded about rotor body 756 (see, e.g., FIG. 7E).Moreover, flux conducting material 758 may suitably be threaded throughand/or otherwise coupled to any suitable portion of rotor body 756, asdesired.

Once flux conducting material 758 is coupled to rotor body 756, fluxconducting 758 and/or rotor body 756 may be processed, formed, shaped,and/or otherwise configured, as desired, for example in order to formone or more flux switches. In an exemplary embodiment, portions of fluxconducting material 758 extending beyond trenches in rotor body 756 areground off to form a substantially smooth surface. Moreover, portions offlux conducting material 758 may be cut, ground, abraded, sliced,polished, and/or otherwise mechanically and/or chemically processed inorder to form one or more flux switches.

With reference now to FIGS. 7B and 7C, portions of flux conductingmaterial 758 remaining within rotor body 756 may act as flux switches,for example when coupled to partial stator 710. In various exemplaryembodiments, folded rotor 750 may provide a “many to many” fluxswitching arrangement similar to that of multipath rotor 550. Moreover,folded rotor 750 may also provide a “one to one” flux switchingarrangement, as desired.

Additionally, in various exemplary embodiments, folded rotor 750 mayhave variable spacing between flux switches as discussed above withrespect to multipath rotor 550, for example in order to generatevariable torque when engaged with a commutated flux machine.

Moreover, various principles applicable to molded rotors and/or foldedrotors may be applied to stators and/or other components of transverseand/or commutated flux machines. For example, a stator may be formed viafolding a material in order to form a flux switch.

Principles of the present disclosure may suitably be combined withprinciples for stators in transverse flux machines and commutated fluxmachines as disclosed in co-pending U.S. patent application Ser. No.12/611,728 filed on Nov. 3, 2009, now published as U.S. PatentApplication Publication No. 2010/0109462 and entitled “TRANSVERSE AND/ORCOMMUTATED FLUX SYSTEM STATOR CONCEPTS”, the contents of which arehereby incorporated by reference in their entirety.

Principles of the present disclosure may also suitably be combined withprinciples of polyphase transverse flux machines and polyphasecommutated flux machines as disclosed in co-pending U.S. patentapplication Ser. No. 12/611,737 filed on Nov. 3, 2009, now published asU.S. Patent Application Publication No. 2010/0109453 and entitled“POLYPHASE TRANSVERSE AND/OR COMMUTATED FLUX SYSTEMS”, the contents ofwhich are hereby incorporated by reference in their entirety.

Moreover, principles of the present disclosure may suitably be combinedwith any number of principles disclosed in any one of and/or all of theco-pending U.S. patent applications incorporated by reference herein.Thus, for example, a particular transverse and/or commutated fluxmachine may incorporate use of a multipath rotor, use of a partialstator, use of a polyphase design, and/or the like. All suchcombinations, permutations, and/or other interrelationships areconsidered to be within the scope of the present disclosure.

While the principles of this disclosure have been shown in variousembodiments, many modifications of structure, arrangements, proportions,the elements, materials and components, used in practice, which areparticularly adapted for a specific environment and operatingrequirements may be used without departing from the principles and scopeof this disclosure. These and other changes or modifications areintended to be included within the scope of the present disclosure andmay be expressed in the following claims.

In the foregoing specification, the invention has been described withreference to various embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the present disclosure. Accordingly,the specification is to be regarded in an illustrative rather than arestrictive sense, and all such modifications are intended to beincluded within the scope of the present disclosure. Likewise, benefits,other advantages, and solutions to problems have been described abovewith regard to various embodiments. However, benefits, advantages,solutions to problems, and any element(s) that may cause any benefit,advantage, or solution to occur or become more pronounced are not to beconstrued as a critical, required, or essential feature or element ofany or all the claims. As used herein, the terms “comprises,”“comprising,” or any other variation thereof, are intended to cover anon-exclusive inclusion, such that a process, method, article, orapparatus that comprises a list of elements does not include only thoseelements but may include other elements not expressly listed or inherentto such process, method, article, or apparatus. Also, as used herein,the terms “coupled,” “coupling,” or any other variation thereof, areintended to cover a physical connection, an electrical connection, amagnetic connection, an optical connection, a communicative connection,a functional connection, and/or any other connection. When languagesimilar to “at least one of A, B, or C” is used in the claims, thephrase is intended to mean any of the following: (1) at least one of A;(2) at least one of B; (3) at least one of C; (4) at least one of A andat least one of B; (5) at least one of B and at least one of C; (6) atleast one of A and at least one of C; or (7) at least one of A, at leastone of B, and at least one of C.

STATEMENTS OF INVENTION

An electrical machine, comprising a multipath rotor comprising a firstset of elbows on a first side of the rotor and a second set of elbows ona second side of the rotor, wherein the first set of elbows arepositioned on the rotor to align with at least one of a first set offlux concentrating stator portions having a first polarity, wherein thesecond set of elbows are positioned on the rotor to align with at leastone of a second set of flux concentrating stator portions having asecond polarity different from the first polarity, wherein theelectrical machine is at least one of a transverse flux machine or acommutated flux machine. The rotor may provide a flux path from one ofthe first set of flux concentrating stator portions to each of thesecond set of flux concentrating stator portions. The rotor may comprisematerial with a bulk saturation induction in excess of 1.0 Tesla. Therotor may comprise material with a bulk permeability in excess of1,000μ. The rotor may comprise alternating layers of a first materialand a second material. The first material and the second material may bedifferent. The first material may be selected to improve machineabilityof the multipath rotor. The first material may be silicon steel and thesecond material may be nanocrystalline composite. The rotor may have abulk permeability in excess of 1,000μ. The rotor may have a bulksaturation induction in excess of 1.0 Tesla. The rotor may bemonolithic. The rotor may direct airflow across a portion of a stator.The rotor may be cavity engaged with a stator. The rotor may be faceengaged with a stator. The electrical machine may be an axial gapmachine. The electrical machine may be a radial gap machine. The rotormay comprise a stamped planar material that is coiled to form a portionof the rotor. The electrical machine may be passively cooled.

An electrical machine, comprising a multipath rotor comprising a firstset of elbows on a first side of the rotor and a second set of elbows ona second side of the rotor, wherein the multipath rotor comprises amaterial having a bulk permeability in excess of 1,000μ, and wherein theelectrical machine is at least one of a transverse flux machine or acommutated flux machine. The multipath rotor may have a bulk saturationinduction in excess of 1.0 Tesla.

A method of making a multipath rotor for an electrical machine, themethod comprising cutting a planar material to form a strip of planarmaterial comprising a first set of elbows on a first side of the planarmaterial and a second set of elbows on a second side of the planarmaterial, wherein adjacent elbows in the strip of planar material areoriented in opposite directions; aligning a plurality of strips ofplanar material such that the elbows on the plurality of strips ofplanar material are in alignment; and bonding the plurality of strips ofplanar material to form a multipath rotor having a first set of fluxswitches on the first set of elbows and a second set of flux switches onthe second set of elbows, wherein the electrical machine is at least oneof a transverse flux machine or a commutated flux machine. Each cutstrip of planar material may be patterned similarly to the other cutstrips of planar material in the multipath rotor, and the cut strips maybe layered parallel to the rotational plane of the multipath rotor. Acut strip may be wound about a mandrel, and each successive cut stripmay be wound about the last. The cut strips may be wrapped assuccessively larger diameter cylinders. A cut strip may be wound about amandrel to form multiple layers. The multipath rotor may comprise aplurality of layers of planar material configured to conduct magneticflux substantially within the layer. The multipath rotor may have a bulkpermeability in excess of 1,000μ. The multipath rotor may have a bulksaturation induction in excess of 1.0 Tesla. The multipath rotor may becoupled to a stator in a commutated flux machine. The planar materialmay comprise at least one of: silicon steel, amorphous metal, ornanocrystalline composite. One of the plurality of layers may comprise afirst material, and another of the plurality of layers may comprise asecond material different from the first material.

A method of making a rotor for an electrical machine, the methodcomprising forming a rotor frame, wherein the rotor frame comprises afirst material having a permeability less than 2μ; and coupling a fluxswitch to the rotor frame to form a rotor for the electrical machine,wherein the flux switch comprises a second material having a saturationinduction in excess of 1.0 Tesla, and wherein a first surface of theflux switch aligns with a first pole of the electrical machine and asecond surface of the flux switch aligns with a second pole of theelectrical machine in order to conduct magnetic flux. A recess may beformed in the rotor frame to accept the flux switch. The rotor frame maycomprise a recess configured to accept the flux switch, and the recessmay be configured to align the flux switch at an angle with respect tothe rotational plane of the rotor. The angle may be selected as afunction of a width of an air gap of the electrical machine and adistance between poles in the electrical machine. The angle may bebetween 5 degrees and 70 degrees. The flux switch may be molded withinthe recess.

An electrical machine, comprising: a mechanically formed rotor, therotor comprising a plurality of flux switches each having a firstsurface and a second surface, wherein the first surface of one of theplurality of flux switches aligns with a first stator pole of theelectrical machine and the second surface of the same one of theplurality of flux switches aligns with a second stator pole of theelectrical machine, and wherein the electrical machine is at least oneof a transverse flux machine or a commutated flux machine. Themechanically formed rotor may be a multipath rotor. The flux switchesmay comprise material with a bulk saturation induction in excess of 1.0Tesla. The flux switches may comprise material with a bulk permeabilityin excess of 1,000μ. The alignment of the first and second surfaces maybe configured to cause each flux switch of the plurality of fluxswitches to close a magnetic circuit in the electrical machine. Therotor may be formed via at least one of: sintering, CNC machining, tapewinding, laser cutting, stamping, die cutting, or water jet cutting. Theflux switches may be angled with respect to the rotational plane of therotor. A geometric configuration of each of the plurality of fluxswitches may be configured to cause each of the plurality of fluxswitches to close a magnetic circuit in the electrical machine. Thegeometric configuration may be a function of at least one of: a switchangle, an engagement depth, a switch height, a switch thickness, aswitch area, a concentrator thickness, or a magnet thickness. The fluxswitch angle may be between about 5 degrees and about 70 degrees withrespect to the rotational plane of the rotor. The rotor may bemechanically formed from a planar material substantially as wide as anair gap of the electrical machine. The flux switch angle may be afunction of a width of an air gap of the electrical machine and anon-center distance between poles in the electrical machine. Theplurality of flux switches may be angled at about 90 degrees withrespect to the rotational plane of the rotor, and a flux concentratingstator portion of the electrical machine may be non-planar. The rotormay comprise at least one of: silicon steel, amorphous metal, powderedmetal, plated powdered metal, or nanocrystalline composite. The rotormay be configured to support a switching frequency in the electricalmachine in excess of 1000 Hz.

An electrical machine, comprising: a rotor comprising a molded rotorframe and a flux switch, wherein the molded rotor frame comprises afirst material having a permeability less than 2μ, wherein the fluxswitch comprises a second material having a saturation induction inexcess of 1.0 Tesla, wherein the flux switch is coupled to the moldedrotor frame, wherein a first surface of the flux switch aligns with afirst pole of the electrical machine, wherein a second surface of theflux switch aligns with a second pole of the electrical machine in orderto conduct magnetic flux, and wherein the electrical machine is at leastone of a transverse flux machine or a commutated flux machine. Themolded rotor may provide a flux path from one of a first set of fluxconcentrating stator portions to each of the second set of fluxconcentrating stator portions. The molded rotor may be cavity engagedwith a stator. The molded rotor may be face engaged with a stator. Theelectrical machine may be an axial gap electrical machine. Theelectrical machine may be a radial gap electrical machine. The firstmaterial may comprise a polymer. The second material may be at least oneof amorphous metal, silicon steel, or nanocrystalline composite. Theflux switch may be set flush to a surface of the molded rotor frame. Aportion of the flux switch may extend outwardly beyond a surface of themolded rotor frame.

A multipath rotor for an electrical machine, wherein the rotorcomprises: a first set of elbows on a first side of the multipath rotor;a second set of elbows on a second side of the multipath rotor oppositethe first side; wherein the multipath rotor comprises a generallyannular shape; wherein the multipath rotor is configured to serve as aflux switch in the electrical machine by transferring flux from one ormore of the first set of elbows to one or more of the second set ofelbows, and wherein the electrical machine is at least one of atransverse flux machine or a commutated flux machine.

1. An electrical machine, comprising: a multipath rotor comprising afirst set of elbows on a first side of the rotor and a second set ofelbows on a second side of the rotor, wherein the first set of elbowsare positioned on the rotor to align with at least one of a first set offlux concentrating stator portions having a first polarity, wherein thesecond set of elbows are positioned on the rotor to align with at leastone of a second set of flux concentrating stator portions having asecond polarity different from the first polarity, and wherein theelectrical machine is at least one of a transverse flux machine or acommutated flux machine.
 2. The electrical machine of claim 1, whereinthe rotor provides a flux path from each one of the first set of fluxconcentrating stator portions to each one of the second set of fluxconcentrating stator portions.
 3. The electrical machine of claim 1,wherein the rotor comprises layers of planar material.
 4. The electricalmachine of claim 1, wherein a first elbow of the first set of elbowsaligns with a flux concentrating portion of a first stator, and whereina second elbow of the first set of elbows aligns with a fluxconcentrating portion of a second stator, the first elbow and the secondelbow being adjacent within the first set of elbows.
 5. The electricalmachine of claim 1, further comprising a plurality of statorsoperatively coupled to the rotor.
 6. The electrical machine of claim 1,wherein the rotor is coupled to at least one of: an automobile wheel, abicycle wheel, a scooter wheel, a propeller, a machine tool, or a drumof a washing machine.
 7. The electrical machine of claim 1, wherein theengagement depth of the rotor with a stator is variable in order to varyat least one of: a voltage constant of the electrical machine, a torqueconstant of the electrical machine, an efficiency level of theelectrical machine, or an RPM of the electrical machine.
 8. Theelectrical machine of claim 1, wherein the electrical machine has acontinuous, thermally stable torque density in excess of 50Newton-meters per kilogram.
 9. The electrical machine of claim 8,wherein the electrical machine has a diameter less than 14 inches. 10.The electrical machine of claim 1, wherein a first subset of the elbowsin the first set of elbows are configured with a first on-centerdistance between elbows, wherein a second subset of the first set ofelbows are configured with a second on-center distance between elbows,and wherein the first on-center distance and second on-center distanceare different.
 11. The electrical machine of claim 1, wherein the rotoris configured to support a magnetic flux switching frequency in theelectrical machine in excess of 1000 Hz.
 12. The electrical machine ofclaim 1, wherein the rotor comprises a material having a saturationinduction in excess of 1.0 Tesla.
 13. The electrical machine of claim 1,wherein the rotor is configured with a bulk permeability in excess of1,000μ.
 14. The electrical machine of claim 1, wherein the rotorcomprises alternating layers of a first material and a second material.15. The electrical machine of claim 14, wherein the first materialcomprises silicon steel, and wherein the second material comprisesnanocrystalline composite.
 16. The electrical machine of claim 1,wherein the first side and the second side are concentric.
 17. Theelectrical machine of claim 1, wherein the first side and the secondside are divisible by a plane perpendicular to the axis of rotation ofthe electrical machine.
 18. The electrical machine of claim 3, whereinone of the layers of planar material comprises silicon steel, andwherein another of the layers of planar material comprisesnanocrystalline composite.
 19. The electrical machine of claim 3,wherein one of the layers of planar material comprises nanocrystallinecomposite, and wherein another of the layers of planar materialcomprises amorphous metal.